An autonomous traveling (automatic traveling) technique and a drive assistant technique for controlling travel of a moving body, such as a robot or an automobile has been developed. Such techniques detect information of surrounding environment to control the travel in accordance with the situation, thus improving safety and convenience. The autonomous traveling estimates a traveling position of the moving body with, for example, accumulated information of speed and angular speed measured by an inertial measurement unit (IMU) or by position measurement using a global positioning system (GPS). The autonomous traveling detects travel lanes and road marks (stop lines, arrows, crosswalks) drawn on the road, or road signs installed on the roadside using a monocular camera, a stereo camera, a laser sensor, and so on, and uses such road marks and road signs as landmarks to control correction of the traveling position or stopping of the moving body. This requires a landmark recognition device capable of recognizing a landmark with a small processing load and high reliability.
In a past example of recognizing landmarks with a small processing load and high reliability, PTL 1 discloses, for example, “an image recognition device including an imaging device, a luminance change detection section that detects a luminance change of a horizontal line, a grouping section that determines the presence of a first horizontal line including a distribution pattern in which first and second luminance changes repeat alternately, a crosswalk candidate region extraction section that extracts a set of consecutive first horizontal lines as a candidate region of the crosswalk, a distance calculation section that calculates a distance to each set, and a crosswalk recognition section that recognizes the crosswalk by excluding the set having a distance equal to or larger than the threshold and determining the set having a distance smaller than the threshold as a region including the crosswalk”. PTL 1 can recognize the crosswalk with high accuracy using a monocular camera.